The present invention relates to a battery module that includes a plurality of battery cells connected to each other. If an internal short circuit is formed in one of the battery cells, the affected battery cell could become very hot, and could be permanently damaged. Further, the affected battery cell could catch on fire, and the fire could spread to the other battery cells within the battery module, causing the entire battery module to burn.
Related art systems use a variety of measures to ensure that an internal short circuit does not pose a significant safety threat to the occupants of a vehicle or the users of an electronic device that is equipped with the battery module. For example, an electronic sensor, such as a thermocouple, may be used to measure the temperature of each battery cell within the battery module. If the temperature of one of the battery cells exceeds a first threshold, the battery module is cooled, and if the temperature of one of the battery cells exceeds a second threshold that is higher than the first threshold, the battery module is turned off. However, this approach requires expensive electronic components, and may require the entire battery module to be shut down if the affected battery cell becomes too hot.
As another example, simple mechanical measures may be used to secure the battery module in the event of an internal short circuit and a subsequent thermal runaway. After the internal short circuit occurs, gas is produced as a result of the heat generated within the affected battery cell. In order to prevent an uncontrolled explosion, a breaker plate or a gas vent may be used to direct the gas away from the other battery cells. Further, the affected battery cell may be disconnected from the battery module. However, the affected battery cell is only disconnected when a significant portion of the thermal energy has already been released into the battery cell, such that it might not be possible to prevent an exothermal runaway of the battery cell.
Further, the state-of-charge window of related art battery modules is limited due to safety concerns related to potential events, such as lithium plating and overcharge events, which may trigger internal short circuits. Accordingly, it would be advantageous to provide a method of reducing the effects of an internal short circuit within a battery cell.